Generally, a battery comprises a battery cell and a PCM. The battery cell includes an electrode assembly being composed of positive electrodes, negative electrodes, and separators, and a case for containing the electrode assembly such that electrode terminals of the electrode assembly are protruded therefrom and a designated quantity of electrolyte is contained therein. The PCM includes a plate installed outside the battery cell and provided with a protection circuit electrically connected to the electrode terminals of the battery cell, and external input/output terminals installed on a side of the protection circuit plate opposite to the battery cell and connected to an external device (for example, a wireless terminal, a notebook computer, or an electric car).
Hereinafter, with reference to FIGS. 1, 2 and, one example of methods for manufacturing the above-described battery will be described in detail.
A battery 1 including a PCM 2 and a battery cell 3, which are integrated with each other, is manufactured by injecting a molten resin into an inner space 5 of a mold including a pair of top mold 4a and bottom mold 4b through an inlet 4aa of the top mold 4a, under the condition that a connection terminal 2aa of a protection circuit plate 2a of the PCM 2 and a lead 3a of the battery cell 1 are connected.
However, the above conventional method wherein the battery cell 3 containing the electrode assembly and the PCM 2 are located in the inner space 5 of the mold and are fixed by the molten resin, has several problems as follows.
First, since the manufacture of the battery is performed while the circuit operates, when the battery cell 3 and the PCM 2 are integrated with each other, the battery cell 3 and the PCM 2 contact the mold, thereby increasing the possibility of short circuit.
Second, when the top mold 4a and the bottom mold 4b are connected under the condition that the battery cell 3 and the PCM 2 are temporarily connected to each other in the inner space 5 of the mold, pressure is applied to the outer surface of the battery cell 3, particularly along the thickness of the battery cell 3, thereby causing the battery cell 3 to be deformed.
Third, when the molten resin of high-temperature and high-pressure states is injected into the inner space 5 of the mold, the injected molten resin distorts the positions of the battery cell 3 and the PCM 2, thereby causing failures.
Fourth, the battery cell 3 in the mold, which reaches a high temperature, changes characteristics of the battery and causes explosion of the battery. Further, where pressure is applied to a battery case of the battery cell 3 in the mold, the pressure is imposed on a welding portion between a battery can and a top cap of the battery can, thereby generating vents at the welding portion.
Fifth, since the manufacture of the battery is performed while that power is applied to the circuit, the output terminal needs to be coated in order to prevent short circuit, thereby supplying inconvenience to workers.
Accordingly, since the conventional method for manufacturing the battery has the above many problems, a technique for solving the above problems is strongly required.